FDNY Lieutenant (LT) Practice Test

The correct answer indicates that the unit designation on straight portable ladders is marked within 18 inches of each butt. This placement is significant as it ensures visibility and easy identification of the ladder's unit during emergency operations and maintenance checks. Marking the designation closer to the butt end rather than at the middle helps fire personnel quickly locate the unit designation when the ladder is in use or positioned in a way where the middle might be less accessible. This practice focuses on efficiency and safety, allowing for rapid response and coordination in critical situations.

Other marking distances, like 10 or 12 inches, may not accommodate the necessary visibility when the ladder is deployed or could be obscured by the ladder's positioning or any equipment that is being used alongside it. The chosen distance of 18 inches balances the need for easy identification with practical use on the ground.